Avocado is the one fruit that is mostly fat, 15g per 100g, so a sinh to bo starts heavy before anything sweet goes in. A cart uses about half a large avocado, 120g, which is 190 calories. Then 30g of condensed milk at 100, 60ml of fresh milk at 40 and a spoon of sugar at 20. That is 350 before the ice, which Long Chau rounds to 300 to 400 per glass. It is the heaviest sinh to on the cart by a wide margin.
It is also the most filling. A glass has 7g of fibre and 22g of fat, and it takes 10 minutes to get through with a spoon. People who replace a banh mi (500) with a sinh to bo (340) for breakfast usually stay full longer, which is unusual for a drink. The trap is having it as a drink with a meal, because 340 on top of a 700 calorie com tam is a 1,040 calorie lunch.
The sweetener choice is the lever. Huggies works out a glass with 100g of avocado, 120ml of fresh milk and a little sugar at 220 to 250. The same glass made with condensed milk, which is what most carts do because it keeps without a fridge, is 340. Sinh to bo sau rieng, with durian blended in, is 480. Kem bo, the Da Lat version with a scoop of ice cream on top, is 500.